US7674382B2 - Method of cleaning fouled and/or scaled membranes - Google Patents
Method of cleaning fouled and/or scaled membranes Download PDFInfo
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- US7674382B2 US7674382B2 US11/743,993 US74399307A US7674382B2 US 7674382 B2 US7674382 B2 US 7674382B2 US 74399307 A US74399307 A US 74399307A US 7674382 B2 US7674382 B2 US 7674382B2
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
- B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/04—Backflushing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/08—Use of hot water or water vapor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/16—Use of chemical agents
- B01D2321/168—Use of other chemical agents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/28—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling by soaking or impregnating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/32—By heating or pyrolysis
Definitions
- This invention pertains to a method of cleaning fouled and/or scaled ultrafiltration and microfiltration membranes using thermoresponsive polymers.
- Ultrafiltration (UF) and microfiltration (MF) are increasingly being used for purification, concentration or fractionation of feed components in water and wastewater treatment, and in industrial processes.
- the benefits of membrane processes include lower energy requirement, much better product quality, smaller footprint and ease of operation.
- UF and MF processes serve as an excellent pre-treatment option for nanofiltration and reverse osmosis in water and wastewater treatment.
- membrane fouling which affects membrane performance negatively in terms of flux and separation characteristics, which in turn, results in higher capital and operating cost for a given through put and product quality.
- Membrane fouling could be of biological, colloidal, particulate or scaling in nature. Therefore, in addition to preventive measures, effective membrane cleaning is equally important for economic operation of UF and MF plants.
- Membrane cleaning processes usually consist of removing the membrane system from service, rinsing the membrane system with high quality water, preparing a cleaning solution, heating the cleaning solution, circulating the cleaning solution at low pressure through the membranes and back into the clean-in-place (CIP) tank.
- the process may also include alternating periods of circulating the cleaning solution through the system and soaking the system in the cleaning solution.
- the system may also be rinsed and fresh cleaning solution applied as needed. Finally the system is rinsed with permeate quality water and either subjected to a second cleaning or placed back in service.
- backwashing with or without chemical is commonly practiced to control particulate and colloidal fouling.
- the present disclosure provides for method of cleaning a fouled and/or scaled UF or MF membrane in a membrane separation system comprising: (a) treating the membrane in a membrane separation system with a solution containing one or more TRP, wherein said TRP is soluble in said solution and at least an effective amount of said TRP diffuses into a foulant layer that is present on the surface and/or in the pores of said membrane; (b) making insoluble said TRP diffused into said foulant layer; (c) optionally, rinsing the membrane; (d) optionally backwashing the membrane with air and/or liquid between the steps (b) and (c); and (e) optionally backwashing the membrane with air and/or liquid after the membrane is rinsed in step (c).
- the foulant layer could be organic and/or inorganic in nature.
- FIG. 1 shows a general schematic of how a TRP facilitates the removal of foulant that is located on a membrane surface and/or in pores of the membrane.
- FIG. 2 shows a bar graph of deionized water flux through a membrane before treatment and after treatment with TRP.
- FIG. 3 shows a bar graph of deionized water flux through a membrane before treatment and after treatment with TRP.
- TRP thermoresponsive polymer
- MM means million.
- UF means ultrafiltration
- MF means microfiltration
- Soluble means completely soluble or maximum swollen in solution below LCST of TRP.
- the scope of this invention is applicable to various types of water containing process systems. These water systems include, but are not limited to, wastewater systems, e.g. wastewater systems that utilize a membrane biological reactor, industrial water systems, and municipal water systems.
- wastewater systems e.g. wastewater systems that utilize a membrane biological reactor, industrial water systems, and municipal water systems.
- Treating the membrane with a TRP solution can occur via various mechanisms. Circulating a TRP containing solution in a membrane separation system or soaking a membrane in a membrane separation system are among several approaches to facilitating the transfer of TRP into a membrane.
- the membrane is treated with a solution containing TRP by circulating said solution in said membrane separation system.
- the membrane is treated with a solution containing TRP by soaking said membrane separation system with said solution.
- the membrane is treated with a solution containing TRP through a backwash, i.e. it is added from a permeate side to the feed side of membrane to remove foulants from the pores.
- the LCST of said TRP solution may be adjusted by adding solvents, hydrotropes, salts, surfactants or combination thereof to the pure TRP solution, prior to treating the membrane surface.
- FIG. 1 shows a general schematic of how thermoresponsive polymers facilitate the removal of foulant that is located on a membrane surface and/or in the pores of a membrane.
- the membrane is first treated with TRP at a temperature below LCST, which makes it soluble in solution.
- the TRP a portion or all of it, then diffuses into the foulant layer that is present on the surface and/or pores.
- TRP is then made insoluble by adding a solution, e.g. containing water or cleaner, under conditions so that the solution temperature is above LCST.
- a solution e.g. containing water or cleaner
- the membrane may be rinsed so that residual TRP and foulant is removed from the membrane.
- the rinsing step may occur by flushing and/or back flushing the membrane under conditions below LCST.
- Making the diffused TRP insoluble or soluble in solution can occur by altering the temperature of the solution.
- the TRP is made insoluble by raising the temperature of said solution above the LCST of said TRP.
- a cleaner is added to the solution before raising the temperature above LCST.
- the TRP is made insoluble by adding a subsequent solution that is above the LCST of said TRP.
- the TRP solution is made insoluble by back-flushing the membrane with water or a cleaner solution that is above LCST of said TRP.
- the TRP is made insoluble by a combination of circulating, soaking and back flushing a membrane with a cleaner solution that is above LCST of TRP.
- the steps of circulating, soaking and back flushing can occur wither sequentially or simultaneously.
- Rinsing the membrane surface can occur via various routes known to those of ordinary skill in the art.
- the membrane is rinsed with a solution that contains water.
- the solution temperature is below the LCST of said TRP. In another embodiment, the solution temperature is above LCST of said TRP.
- the membrane is rinsed by back flushing with a solution that contains water.
- the solution temperature is below the LCST of said TRP.
- the membrane is rinsed by combination of flushing and back flushing the membrane system with a solution that contains water.
- the solution temperature is below the LCST of said TRP.
- membranes may be optionally backwashed with air and/or liquid between the steps of cleaner solution treatment above LCST and rinsing with solution below LCST.
- the membranes are optionally backwashed with air and/or liquid after rinsing, e.g. final rinsing, with solution below LCST.
- the solution temperature may be altered via several different routes.
- a solution is circulated with the requisite temperature to alter the solubility of the TRP.
- a solution that is soaking the membrane may be heated by an external source.
- a solution with the requisite temperature is back-flushed to alter the solubility of the TRP.
- TRP's are effective in facilitating the cleaning of UF and MF containing membranes.
- the TRP is poly(N-isopropyl acrylamide).
- Poly(N-isopropyl acrylamide) is a well known thermo-responsive polymer (TRP), which undergoes a phase transition at 32-33° C., i.e. it is soluble below this temperature and as this temperature approaches, polymer chains collapse and subsequently above this temperature, they aggregate and become insoluble.
- the membrane when the membrane is treated with a poly(N-isopropyl acrylamide) containing solution, the solution is at 25-30° C .
- the TRP is selected from the group consisting of: polyethylene oxide (PEO), polypropylene glycol (PPG), poly[N-(2,2-dimethoxyethyl)-N-methylacrylamide], ethylene oxide (EO)-Propylene Oxide (PO) copolymer, polyvinylmethyl ether (PVME), poly(2-ethyl oxazoline) (PEOX), Hydroxypropyl cellulose (HPC), ethyl hydroxyethyl cellulose (EHEC), vinylalcohol-vinyl acetate copolymer, Poly(vinyl pyrrolidone), PVME-graft-PEO, elastin like polypeptides, and a combination thereof.
- PEO ethylene oxide
- PO ethylene oxide
- PVME polyvinylmethyl ether
- PVME poly(2-ethyl oxazoline)
- HPC Hydroxypropyl cellulose
- EHEC ethyl hydroxyethyl
- TRP added to the system depends upon the chemical and physical nature of the foulant layer, extent of fouling on the surface and in the pores of the membrane that is being cleaned, location of TRP injection before membrane system, a method of TRP injection (circulation, soaking, back-flushing etc), a combination of these factors, or other factors, which would be apparent to one of ordinary skill in the art.
- an effective amount of TRP is from about 1 ppm to about 5000 ppm, based upon active solids in the solution.
- the molecular weight of the TRP may range from about 1,000 to about 20 MM daltons, preferably from about 1000 to about 100,000 daltons.
- the treatment of a membrane with the TRP containing solution occurs for about 10 minutes to about 8 hours, preferably for about 10 minutes to about 120 minutes.
- the time between first backwash to treat membrane with TRP solution below LCST and another backwash with solution above LCST of TRP to make it insoluble may be between 2 minutes to 180 minutes, preferably between 10 min to 60 minutes.
- the methodology in the present disclosure may be applied to UF and MF membrane systems.
- the membrane is polymeric.
- the membrane is inorganic.
- the membrane is stainless steel.
- the membrane is selected from asymmetric or composite membranes.
- the membrane has hollow fiber (both outside-in and inside-out filtration type) configuration.
- the membrane has capillary configuration.
- the membrane has a flat sheet configuration.
- the membrane has a spiral wound configuration.
- the membrane has a tubular configuration.
- the membrane has multi-bore structure.
- the membrane is submerged in a feed solution tank.
- the membrane is external to the feed tank.
- the cleaning process may be applied to various types of UF membranes.
- the UF membrane has a pore size of 0.003-0.1 ⁇ m.
- the cleaning process may be applied to various types of MF membranes.
- the MF membrane has pore size of 0.1-10 ⁇ m.
- This method of cleaning may be used as a partial or complete CIP (Clean-in-place) or may be combined with Chemically Enhanced Backwash (CEB) cycle.
- CIP Chemically Enhanced Backwash
- this method of cleaning may be applied in the same tank as used for processing feed or the membrane may be transferred to another tank for cleaning.
- membrane-scouring air may or may not be kept on during various steps of the cleaning process of this invention.
- a cleaner may be added to a membrane separation system via various routes.
- the solution containing TRP contains a cleaner.
- a cleaner is added to the solution containing TRP.
- the membrane is treated with a solution containing cleaner.
- cleaners may be utilized to a clean a membrane separation system.
- the cleaner contains water.
- the cleaner contains chlorine dioxide, chlorous acid, chloramines, sodium hypochlorite, bromine, bromous acid, sodium bromate, an oxyhalogen compound, or a combination thereof.
- the cleaner contains hydrogen peroxide, peracetic acid, sodium percarbonate, permanganates, or a combination thereof.
- the cleaner contains cyclic nitroxyl compound such as 2,2,6,6-tetramethylpiperidine N-Oxyl (TEMPO) and oxyhalogen compound such as sodium hypochlorite.
- TEMPO 2,2,6,6-tetramethylpiperidine N-Oxyl
- oxyhalogen compound such as sodium hypochlorite.
- U.S. Pat. No. 7,052,557 provides a further description of this cleaner and is herein incorporated by reference.
- the nitroxyl compound is 2,2,6,6-tetramethylpiperidine N-Oxyl (TEMPO).
- the cleaner contains 2,2,6,6-tetramethylpiperidine N-Oxyl (TEMPO) and an oxyhalogen compound.
- TEMPO 2,2,6,6-tetramethylpiperidine N-Oxyl
- the oxyhalogen compound is sodium hypochlorite.
- the cleaner contains anionic surfactants, non-ionic surfactants, cationic surfactants, zwitterionic surfactants, or a combination thereof.
- anionic surfactants are selected from the group consisting of: aliphatic organic phosphate esters; linear and branched alkylaryl sulfonates and derivatives thereof; linear and branched alkylaryl ether sulfonates and derivatives thereof; alpha olefin sulfonate; ammonium alcohol ethoxylate sulfate; ammonium alkyl ether sulfates; ammonium alkyl sulfates; alkyl sulfates; alcohol amine alkyl sulfates; alkyl sulfosuccinate salts; alkyl sulfonates and salts thereof; alkyl ether sulfonates and salts thereof; fatty alcohol ether sulfates; sulfates of alcohol; sulfonates of petroleum and petroleum derivatives; sulfonated oils and fatty acids; and a combination thereof.
- nonionic surfactants are selected from the group consisting of: alkanolamides; alkanol amide alkoxylates; alkoxylated alkyl amines; alkoxylated alkyl alcohols alkoxylated alcohols; alkyl glucosides; alkyl phenol alkoxylates; alkyl phenol alkoxylated alcohols; alkylated fatty acids; alkoxylated fatty alcohols; linear fatty alcohols, especially C16-C18; alkoxylated alkyl phenols; alkoxylated triglycerides; alkoxylated fatty acids; fatty acid amines; alkoxylated fatty esters and oils; polyol esters; polyoxyalkylene esters of fatty acids; alkyl polysaccharide ethers; aliphatic ethers; polyether glycols; sorbitan derivatives; block copolymers of propylene oxide and ethylene oxide; and a combination thereof
- zwitterionic surfactants are selected from the group consisting of: alkyl ammonium carboxylates, alkyl ammonium sulphates, alkylammonium sulfonates, alkyl amine oxides, alkyl betaines, alkyl sulfobetaines, and a combination thereof.
- cationic surfactants are selected from the group consisting of: single or mixed alkyl substituted ammonium chlorides, single or mixed alkyl substituted ammonium acetates, single or mixed alkenyl substituted ammonium chlorides and acetates, mixed alkyl hydroxyalkyl amidoalkyl substituted ammonium chlorides and acetates, single and mixed alkyl imidazolium salts, and a combination thereof.
- the cleaner contains chelants and/or sequestering agents.
- the cleaner contains enzymes.
- one or more enzymes are selected from the group consisting of lipases; proteases; pectinases, cellulases, gluconases, galactosidases, and amylases.
- the treatment of a membrane with a cleaner can occur via one or more routes.
- membrane cleaning with one or more chemicals known to those of ordinary skill in the art and those approaches may be applied in the present methodology.
- a cleaner may be applied to a membrane in a membrane separation process by circulating a solution containing a cleaner through the membrane separation system, by soaking the membrane in a membrane separation system with a solution containing a cleaner, or by back-flushing the membrane in a membrane separation system with a solution containing cleaner and by a combination thereof.
- the treatment of a membrane with the solution containing a cleaner occurs for about 10 minutes to about 8 hours.
- the treatment of a membrane with the solution containing a cleaner occurs for about 10 minutes to about 180 minutes.
- the temperature of said solution at which TRP is made insoluble is 33-60° C.
- the cleaning performance was determined with the following test sequence.
- Test conditions for measurement of deionized (“DI”) water flux permeate flow per unit time per unit membrane area) before and after cleaning were: 50 psi feed pressure, 25° C. temperature and approximately 200 revolutions per minute (“rpm”) stirring speed in a dead-end filtration stirred cell.
- TRP was poly(N-isopropyl acrylamide). Permeate flow was measured by a weighing balance. A bucket and stopwatch could also be used.
- One coupon (control) was cleaned by soaking in 1% alkaline cleaner D, pH 10.4 at 53° C. for 1 hr, whereas another coupon was cleaned by 1) first exposing it to 100 ppm TRP at 20 psi and 25° C. for 30 min and 2) then soaking it in 1% alkaline cleaner D, pH 10.4 at 53° C. for 30 min. Both coupons were rinsed and soaked in DI water (changed 3 times) for 60 minutes to remove residual cleaner and stabilize the membrane at ambient temperature, before measuring the DI water flux again.
- the DI water fluxes before and after cleaning by the above two methods are shown in FIG. 2 .
- the cleaning performance was determined with the following test sequence.
- Test conditions for measurement of deionized (“DI”) water flux (permeate flow per unit time per unit membrane area) before and after cleaning were: 50 psi feed pressure, 25° C. temperature and approximately 200 revolutions per minute (“rpm”) stirring speed in a dead-end filtration stirred cell.
- TRP was poly(N-isopropyl acrylamide). Permeate flow was measured by a weighing balance. A bucket and stopwatch could also be used.
- Example 2 100 ppm TRP and 1% alkaline cleaner were first mixed together. The membrane was then cleaned by exposing to this solution (pH 10.4) at 20 psi and 25° C. for 30 min, followed by soaking in the same solution at 53° C. for 30 min. The DI water flux results are shown in FIG. 3 .
- this method of cleaning also showed over 250% increase in flux compared to 150% with control (i.e. 1% alkaline cleaner D alone)
Abstract
Description
Claims (21)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/743,993 US7674382B2 (en) | 2007-05-03 | 2007-05-03 | Method of cleaning fouled and/or scaled membranes |
TW097114095A TW200911353A (en) | 2007-05-03 | 2008-04-18 | Method of cleaning fouled and/or scaled membranes |
ARP080101876A AR066427A1 (en) | 2007-05-03 | 2008-05-02 | METHOD FOR CLEANING CONTAMINATED AND OR SCAMED MEMBRANES |
PCT/US2008/062399 WO2008137663A1 (en) | 2007-05-03 | 2008-05-02 | Method of cleaning fouled and/or scaled membranes |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US11/743,993 US7674382B2 (en) | 2007-05-03 | 2007-05-03 | Method of cleaning fouled and/or scaled membranes |
Publications (2)
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US20080271758A1 US20080271758A1 (en) | 2008-11-06 |
US7674382B2 true US7674382B2 (en) | 2010-03-09 |
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US11/743,993 Active US7674382B2 (en) | 2007-05-03 | 2007-05-03 | Method of cleaning fouled and/or scaled membranes |
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US (1) | US7674382B2 (en) |
AR (1) | AR066427A1 (en) |
TW (1) | TW200911353A (en) |
WO (1) | WO2008137663A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100140170A1 (en) * | 2008-11-20 | 2010-06-10 | Alion Science And Technology | Filter cleaning method |
US9074162B1 (en) | 2014-02-07 | 2015-07-07 | Ecolab Usa Inc. | Detergent compositions comprising vinylidene diphosphonic acid polymers |
US9868659B2 (en) | 2015-04-17 | 2018-01-16 | General Electric Company | Subsurface water purification method |
US11738310B2 (en) | 2019-12-31 | 2023-08-29 | Industrial Technology Research Institute | Method for cleaning membrane |
Families Citing this family (8)
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WO2011088505A1 (en) * | 2010-01-19 | 2011-07-28 | Flinders University Of South Australia | Low-fouling filtration membranes |
US9567357B2 (en) * | 2011-06-24 | 2017-02-14 | Biointeractions Ltd. | Biocompatible, biomimetic ampholyte materials |
CN103086941A (en) * | 2012-12-19 | 2013-05-08 | 吉林大学 | N-acryloyl succinimide and synthetic method thereof |
US10946342B2 (en) | 2015-07-13 | 2021-03-16 | King Abdullah University Of Science And Technology | Dynamic coating of MF/UF membranes for fouling mitigation |
CA3014116A1 (en) | 2017-08-18 | 2019-02-18 | Ecolab Usa Inc. | Method for off-line cleaning of cooling towers |
CN109224884B (en) * | 2018-10-16 | 2021-10-01 | 东莞东阳光科研发有限公司 | Polymer film and preparation method and application thereof |
CN110559865B (en) * | 2019-08-14 | 2022-02-25 | 浙江理工大学 | Method for repairing ultrafiltration membrane pollution or membrane damage |
TWI769425B (en) * | 2019-12-31 | 2022-07-01 | 財團法人工業技術研究院 | Method for cleaning membrane |
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- 2008-05-02 WO PCT/US2008/062399 patent/WO2008137663A1/en active Application Filing
- 2008-05-02 AR ARP080101876A patent/AR066427A1/en unknown
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US20100140170A1 (en) * | 2008-11-20 | 2010-06-10 | Alion Science And Technology | Filter cleaning method |
US9238586B2 (en) * | 2008-11-20 | 2016-01-19 | Alion Science & Technology | Filter cleaning method |
US9074162B1 (en) | 2014-02-07 | 2015-07-07 | Ecolab Usa Inc. | Detergent compositions comprising vinylidene diphosphonic acid polymers |
US9868659B2 (en) | 2015-04-17 | 2018-01-16 | General Electric Company | Subsurface water purification method |
US11738310B2 (en) | 2019-12-31 | 2023-08-29 | Industrial Technology Research Institute | Method for cleaning membrane |
Also Published As
Publication number | Publication date |
---|---|
TW200911353A (en) | 2009-03-16 |
WO2008137663A1 (en) | 2008-11-13 |
AR066427A1 (en) | 2009-08-19 |
US20080271758A1 (en) | 2008-11-06 |
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